Device for dynamic separation of two zones

ABSTRACT

A device for dynamically separating two zones by a bufer zone and two clean air curtains. When transferring objects at high speed between two zones, a buffer zone which is connected to the two zones, forms a dynamic lock in order to separate them. a dynamic confinement system placed between each pair of adjacent communication zones forms an air curtain including two or three clean air jets. The buffer zone includes a blower ceiling and an intake grill facing it.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a device used to dynamically separate at leasttwo zones in which there are different environments, to enable objectsor products to be transferred from one zone to the other at high speedwithout breaking the confinement.

The process according to the invention may be used in many industrialsectors.

Thus, this process is applicable to all industries (food processing,medical, biotechnologies, high technologies, nuclear, chemical, etc.) inwhich different environments have to be maintained in zonescommunicating with each other to enable frequent passage of objects orproducts. The term “environment” refers particularly to aeraulicconditions, gaseous and particular concentrations, temperature, relativehumidity, etc.

2. Discussion of the Background

At the present time, there are two types of solutions for dynamicallyseparating two zones communicating with each other, for example in orderto allow objects to be brought in and out; these two types areprotection by ventilation and protection by air curtain.

Protection by ventilation consists of artificially creating a pressuredifference between the two zones so that the pressure in a zone to beprotected is greater than the pressure inside a contaminating zone.Thus, if the zone to be protected contains a product that could becontaminated by ambient air, a laminar flow is injected into the zone tobe protected that blows outwards through the access opening to thisseparation zone. In the opposite case in which personnel and theenvironment outside a contaminated space need to be protected, dynamicconfinement is achieved by using extraction ventilation in thiscontaminated space. In each case, an empirical rule imposes a minimumventilated air speed of 0.5 m/s in the plane of the opening throughwhich the two zones communicate in order to prevent contamination frombeing transferred into the zone to be protected.

However, the efficiency of this ventilation protection technique is notperfect, particularly in a so-called “infractions” situation, in otherwords when objects are transferred between the two zones. Furthnermore,this type of protection makes it necessary to process and control theentire zone to be protected ron the contaminating external atmosphere orthe entire contaminated zone. When the zone to be processed andcontrolled is large, this introduces a particularly high investment andoperating cost. Finally, this technique of protection by ventilationonly provides protection in one direction, in other words it is onlvuseful when contamination transfers are only possible in one direction.

The air curtain protection technique consists of simultaneouslyinjecting one or several adjacent clean air jets in the same directioninto the separation zone between the two zones, which form an immaterialdoor between the zone to be protected and the contaminating zone.

Note that according to the theory of turbulent plane jets, a plane airjet is composed of two separate zones; a transition zone (or core zone)and a development zone.

The transition zone corresponds to the central part of the jet adjacentto the nozzle in which clean air is injected. Within this zone in whichthere is no mix between the injected air and the air on each side of thejet, the speed vector is constant. Considering a cross-section through aplane perpendicular to the plane of the separation zone, the width ofthe transition zone gradually decreases as the distance from the nozzleincreases. This is why this transition zone is called a “tongue”throughout the rest of the text.

The-development zone of the jet is the part of this jet located outsidethe transition zone. In this jet development zone, outside air isentrained by the jet low. This results in variations in the speed vectorand mixing of air. Air entrainment on both surfaces of the jet withinthis development zone is called “induction”. Thus an air jet induces anair flow on each of its surfaces which depends particularly on theinjection flow of the jet considered.

Documents FR-A-2 530 163 and FR-A-2 652 520 propose an air curtain toseparate a polluted zone from a clean zone. in both cases, the aircurtain consists of twio adjacent clean air jets blowing in the samedirection. Nllore precisely, dynamic separation is provided by a firstrelatively slow jet (called the “slow jet”), for which the tongueentirely covers the opening. The second jet (called the “fast jet”) isfaster than the slow jet, and is installed between the slow jet and thezone. Its function is to stabilize the slow jet by a suction effectwhich brings this slow jet into contact with the fast jet.

In these documents, it is specified that the tongue of the slow jet issufficiently long to cover any opening when the width of the slow jetinjection nozzle is equal to at least ⅙^(th) of the height of theopening to be protected.

Document FR-A-2 652 520 also proposes to simultaneously inject cleanventilation air at a temperature adapted to the requirements, inside theclean zone to be protected. Note that this clean ventilation air must beinjected at a rate approximately equal to the rate induced by thesurface of the fast jet which is in contact with clean ventilation air.

Furthermore, document FR-A-2 659 782 proposes to add a third relativelyslow clean air jet to the two clean air jets used in documents FR-A-2530 163 and FR-A-2 652 520 so that the fast jet is located between twoadjacent slow jets in the same direction. The flow of clean ventilationair injected inside the zone to be protected is then considerablyreduced due to the fact that induction in this zone is produced by thedevelopment zone of one of the slow jets, rather than by the developmentzone of the fast jet as in the case of an air curtain with two jets.Furthermore, dynamic confinement is provided in both directions, whichwas not the case in the previous documents.

Document WO-A-96 241011 also describes an installation in which achamber containing a confined atmosphere, communicates with the sameoutside atmosphere through one or two openings, with which gas curtainsare associated. Each gas curtain is formed of a slow jet sustained by afast jet as described in documents FR-A-2 530 163 and FR-A-2 652 520.The chamber can be used for continuous processing of products due to theinjection of a reagent inside it. Products pass from the outsideatmosphere into the confined atmosphere in this chamber to be processedin it before being taken out again to the external atmosphere.

Despite the improvements made to the air curtain technique described inthese various documents, the problem of transferring objects or productsat a high rate between two zones in which there are differentenvironments without breaking the confinement has not beensatisfactorily solved by any known device, particularly if there is arisk of cross-contamination between the two zones.

SUMMARY OF THE INVENTION

More particularly, the purpose of the invention is a device for dynamicseparation of at least two zones in which there are differentenvironments authorizing high speed transfer of objects or productsbetween these zones, without breaking the confinement, even in the casein which there is a risk of cross-contamination between the two zones.

According to the invention, this result is obtained by means of adynamic separation device separating at least two zones in which thereare different environments, characterized by the fact that it comprises:

at least one buffer zone with controlled atmosphere used forcommunication between the zones to be separated;

dynamic confinement means placed between each pair of adjacentcommunicating zones to create an air curtain between these zonescomprising a first relatively slow clean air jet which comprises atongue which completely closes off communication between the zones, anda second relatively fast clean air jet in the same direction as thefirst jet and adjacent to it, on the side of the buffer zone.

The expression “with controlled atmosphere” means that allcharacteristics of the air present in the buffer zone such astemperature, relative humidity, aeraulic conditions, gaseous andparticular concentrations, etc., are controlled.

The expression “adjacent communicating zones” means each group of twozones in the assembly formed by the zones to be separated and by thebuffer zones, that communicate directly with each other. Thus in thecase in which the device comprises a single buffer zone located betweentwo zones to be separated, there are two pairs of adjacent communicatingzones each formed by the single buffer zone and one of the zones to beseparated. When there are several buffer zones, there is at least oneother pair of adjacent communicating zones formed of two buffer zones.

The arrangement consisting of one of several buffer zones between thezones to be separated, and air curtains formed from at least two jets ofclean air between adjacent communicating zones, enable objects orproducts to be transferred at high speed while preventing contaminantspresent in either of the controlled environment zones from reaching theother controlled environment zone, and vice versa. Each buffer zone thusacts as a dynamic lock between the zones to be separated.

Preferably, the dynamic confinement means that are inserted between eachpair of adjacent communicating zones are such that the second (fast) jetin each air curtain is injected at a flow such that the air flow inducedby the surface of the second jet in contact with the first (slow) jet isless and preferably approximately equal to half the first jet injectionrate.

In one special embodiment, these dynamic confinement means are such thateach air curtain comprises a relatively slow third jet in the samedirection as the first and second jets and adjacent to the second (fast)jet on the same side as the buffer zone. This third jet then comprises atongue that completely closes off communication between the zones and itis injected at a flow significantly equal to the injection flow in thefirst jet, so that the air flows induced by the surfaces of the secondjet in contact with the first and third jets respectively are less than,or preferably approximately equal to half of the injection flows of thejets.

In practice, each of the dynamic confinement means comorises at leasttwo adjacent air supply nozzles and an intake grille facing the supplynozzles and located in a plane parallel to them. The supply nozzles andthe intake grilles are advantageously located in line with the upper andlower surfaces of the buffer zone.

In order to further improve the behavior of the device particularly ininfraction situations through air curtains, the buffer zone preferablycomprises ventilation, such as a blower ceiling, associated with theinjection means that inject clean air into this zone. The flow fromthese injection means is then equal to at least the sum of the air flowsinduced by each of the surfaces of the jets in the air curtains incontact with the buffer zone. Furthermore, the flow from the injectionmeans is such that it provides a minimum speed of 0.1 m/s across theareas of the planes at the ends of the buffer zone.

In this case, the buffer zone may also comprise an intake grilledistributed over its entire lower surface. The flow from the injectionmeans is then equal to at least the sum of the air flow drawn in by theintake grille and the air flow induced by each of the surfaces of theair curtain jets in contact with the buffer zone. Furthermore, the flowfrom the injection means must always be sufficient to provide a minimumspeed of 0.1 m/s across the areas of the planes at the ends of thebuffer zone. This arrangement corresponds particularly to the case inwhich the buffer zone is used to carry out an elementary operation(proportioning, packaging, etc.) on objects or products transferredbetween the zones to be separated.

In the latter case, several buffer zones may be placed in series betweenthe zones to be separated. The air curtains inserted between the twobuffer zones are then delimited by side walls with a width equal to thewidth of the adjacent air supply nozzles.

Furthermore, regardless of the number of buffer zones used on thedevice, the air curtains inserted between a buffer zone and one of thezones to be separated are delimited by side walls with a width equal toat least the maximum thickness of these air curtains.

BRIEF DESCRIPTION OF THE DRAWINGS

We will now describe some non-limitative examples of differentembodiments of the invention with reference to the attached drawings inwhich:

FIG. 1 is a perspective view that diagrammatically illustrates the useof a single buffer zone to provide communication between two zones withcontrolled environments through two air curtains each formed of twoadjacent clean air jets according to a first embodiment of theinvention;

FIG. 2 is a perspective view comparable to FIG. 1 which illustrates thecase in which each air curtain is formed of three adjacent clean airjets according to a second embodiment of the invention; and

FIG. 3 is a perspective view that diagrammatically illustrates the useof several buffer zones in series between two zones with controlledenvironments, with the insertion of an air curtain between each pair ofadjacent communicating zones.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows two zones denoted by reference 10 a and 10 b, in whichthere are different environments and in which it is required to be ableto transfer objects or products at high speed in at least one direction.These zones 10 a and 10 b are called the “zones to be separated” or“zones with controlled environments” throughout the rest of this text.For example, it is assumed non-restrictively that objects or productsmust be transferred at high speed from zone 10 a to zone 10 b.

Zones 10 a and 10 b are delimited by air tight surfaces (not shown) andthe environment in each zone is different, in other words at least oneof the characteristics, specifically such as gaseous and particularconcentrations, aeraulic conditions, temperature, relative humidity,etc. is different in the two zones.

According to the invention, zones 10 a and 10 b are linked to each otherthrough at least one dynamic separation system which, in the embodimentshown in FIG. 1, includes a buffer zone 12 through which zones 10 a and10 b communicate. More precisely, the buffer zone 12 is a zone with acontrolled atmosphere, in other words a zone in which various parameterssuch as gaseous and particular concentrations, aeraulic conditions,temperature, relative humidity, etc., are controlled.

The dynamic separation device according to the invention also comprisesdynamic confinement means denoted in general by references 14 a and 14 bon FIG. 1, which are inserted between zone 10 a and buffer zone 12, andbetween buffer zone 12 and zone 10 b respectively, in other words eacnpair of adjacent communicating zones in the installation.

Dynamic confinement means 14 a create a first air curtain 16 a betweenzone 10 a and buffer zone 12. imilarly, dynamic confinement means 14 bcreate a second air curtain 16 b between buffer zone 12 and the zone 12b with controlled environment.

As illustrated diagrammatically in FIG. 1, the buffer zone 12 isdelimited by air tight surfaces in order to form a horizontal corridorwith a rectangular cross-section, the ends of which lead into zone 10 aand into zone 10 b through air curtains 16 a and 16 b created by dynamicconfinement means 14 a and 14 b.

The upper horizontal surface of the buffer zone 12 forms a blowerceiling 18. This blower ceiling 18 is associated with injection orventilation means (not shown) that output clean air to the buffer zone12 at a determined flow. As will be seen later, this flow depends on thecharacteristics of the air curtains 16 a and 16 b and whether or notthere is an intake grille in buffer zone 12.

In the embodiment shown in FIG. 1, the horizontal lower surface 20 ofthe buffer zone 12 forms a working plane. As a variant, an intake grillemay be distributed over this entire lower surface 20, to recover part ofthe ventilation air flow injected into buffer zone 12 through the blowerceiling 18.

In addition to its upper horizontal surface that forms the blowerceiling 18 and its lower horizontal surface 20, the buffer zone 12 isdelimited by two side walls 22, also oriented vertically parallel to theplane of FIG. 1.

The dynamic confinement means 14 a and 14 b are placed in line with theair tight walls that delimit the buffer zone 12 so as to form the aircurtains 16 a and 16 b when these confinement means are used.

More precisely, in the embodiment shown in FIG. 1, dynamic confinementmeans 14 a and 14 b are designed to create air curtains 16 a and 16 beach of which are formed of two clean air jets adjacent to each otherand in the same direction. Consequently, dynamic confinement means 14 acomprise two air supply nozzles 24 a and 26 a that extend across theentire width of buffer zone 12 in line with the blower ceiling 18 on thezone 10 a side. Similarly, dynamic confinement means 14 b comprise twoair supply nozzles 24 b and 26 b that extend across the entire width ofbuffer zone 12 in line with the blower ceiling 18 on the zone 10 b side.All air supply nozzles 24 a, 26 a, 24 b and 26 b output into the samehorizontal plane located in line with the lower surface of the blowerceiling 18.

The dynamic confinement means 14 a also comprise a horizontal intakegrille 28 a located on the surface of the air supply nozzles 24 a and 26a and extend over the entire width of buffer zone 12, in line with itslower surface 20. Similarly, dynamic confinement means 14 b comprise ahorizontal intake grille 28 b placed below the air supply nozzles 24 band 26 b and extending over the entire width of buffer zone 12, in linewith its lower surface 20.

Each of the dynamic confinement means 14 a and 14 b also comprises means(not shown) of injecting air at a controlled speed and flow through theair supply nozzles 24 a and 26 a, and through the air supply nozzles 24b and 26 b respectively, and means (not shown) of drawing in all airflows injected through the nozzles and induced air flows, through intakegrilles 28 a and 28 b respectively.

As shown diagrammatically in FIG. 1, the air tight side walls 22 thatdelimit the buffer zone 12 extend beyond the ends of this zone over alength equal to at least the maximum thickness of the air curtains 16 aand 16 b, in order to avoid any break in the confinement at the sides ofair curtains.

As already mentioned, the embodiment in FIG. 1 corresponds to the casein which each air curtain 16 a and 16 b is formed of two adjacent cleanair jets in the same direction. The two air curtains 16 a and 16 b haveexactly the same characteristics which will now be described in moredetail.

When the dynamic confinement means 14 a and 14 b are used, each of theair supply nozzles 24 a and 24 b outputs a relatively slow clean airjet, for which only tongues 30 a and 30 b are shown. Furthermore, eachof the air supply nozzles 26 a and 26 b located on the same side of theblower ceiling as the nozzles 24 a and 24 b outputs a relatively fastclean air jet compared with the jets output by nozzles 24 a and 24 b.FIG. 1 only shows the tongues 32 a and 32 b of these relatively fastjets. To simplify the description, the relatively slow and relativelyfast jets are called “slow jets” and “Last jets” in the rest of thetext.

Since the air supply nozzles 24 a, 26 a, 24 b and 26 b extend over theentire width of the buffer zone 12, the air curtains 16 a and 16 b alsoextend over the entire width of the burrer zone between the buffer zoneside walls 22.

As shown diagrammatically in Iigure 1, each of the slow jets injected bynozzles 24 a and 24 b is sized such that its tongue 30 a, 30 b coverstne entire cross-section of the buffer zone at the ends of the bufferzone adjacent to zones 10 a and 10 b respectively. This result isobtained by making sure that the range, or length, of the tongues 30 aand 30 b is at least as long as the height of the buffer zone 12. Thisis achieved by making the width of the injection slit for each nozzle 24a and 24 b parallel to the plane of the figure equal to at least ⅙^(th)and preferably ⅕^(th) of the height of the buffer zone 12.

Furthermore, the speed of each of the slow jets emitted by nozzles 24 aand 24 b is advantageously equal to 0.5 m/s, in order to minimizeturbulence and for economic reasons. Since the length of the tongues 30a and 30 b of the slow jets is equal to at least half of the height ofthe buffer zone 12 and since these jets are relatively slow, the airstreams go around the contours of the objects or products that passthrough the air curtains 16 a and 16 b without breaking the confinement.

However, the low speed of the slow jets injected by nozzles 24 a and 24b mean that these jets, if they were alone, could be destabilized byaeraulic or mechanical disturbances that could occur close Lo the aircurtains, thus breaking the confinement of zones 10 a and 10 b. This iswhy fast jets injected by nozzles 26 a and 26 b are added to each of theslow jets. The highest speed of these fast jets stabilizes the slow jetsand consequently improves the confinement efficiency of zones 10 a and10 b in infraction situations through the dynamic barriers forred byeach of the air curtains 16 a and 16 b. As a nonrestrictive example, thewidth of each fast jet air supply nozzle 26 a and 26 b may be equal toabout {fraction (1/40)}^(th) of the width of the slow jet air suoplvnozzles 24 a and 24 b.

Preferably, in order to optimize the barrier effect provided by aircurtains 16 a and 16 b, the injection flow of each fast jet throughnozzles 26 a and 26 b is adjusted such that the air flow induced by thesurfaces of these fast jets that are in contact with the slow jetsinjected through nozzle 24 a and 24 b is less than, or preferablyapproximately equal to half of the injection flow through these slowjets.

As already noted, the intake grilles 28 a and 28 b recover the entireair blown through the supply nozzles under which they are placed, andall entrained air by each air curtain 16 a and 16 b. In practice, airrecovered through intake grilles 28 a and 28 b may be purified byspecific purification means (not shown) before being recycled to airsupply nozzles 24 a, 26 a; 24 b, 26 b. Excess air is then releasedoutside after a second specific purification.

Note that the horizontal orientation of the air supply nozzles thatdetermines a vertical orientation of the air curtains, and thehorizontal arrangement of the intake grilles facing the air curtains,optimize the barrier effect obtained using each of the dynamicconfinement means 14 a and 14 b.

Furthermore, internal ventilation of the buffer zone 12 provided by theblower ceiling 18 produces a purifying effect in this zone. Thispurifying effect contributes to the efficiency of the dynamic separationof zones 10 a and 10 b, particularly in the case of a high transfer rateof objects or products between these two zones.

More precisely, in the embodiment shown in FIG. 1 in which each of theair curtains 16 a and 16 b is formed of two adjacent jets in the samedirection, the clean ventilation air flow injected in the buffer zone 12through the blower ceiling 18 is equal to at least the air flow inducedby the fast jets output from nozzles 26 a and 26 b, on the surfaces ofthese fast jets that are in contact with the buffer zone 12.Furthermore, the clean ventilation air is injected into the buffer zone12 through the blower ceiling 18 at a speed such that the air speedacross the areas of the planes at the ends of the buffer zone 12 thatlead into zones 10 a and 10 b, is equal to at least 0.1 m/s.

Furthermore, note that the physical characteristics (temperature,relative humidity, gaseous and particular concentrations, etc.) arecontrolled by appropriate means (not shown), so as to establish andmaintain a determined atmosphere in Lhe buffer zone 12. This atmospheremay be identical to the atmosphere in one of the two zones 10 a and 10b, or it may be different from this atmosphere, depending on theapplication being considered.

Each of the intake grilles 28 a and 28 b has a width approximately equalto the total width of the air supply nozzles 24 a and 26 a, and 24 b and26 b respectively. However this width may be varied, particularly totake account of some aeraulic conditions in zones 10 a and 10 b, tendingto deviate the jets forming the air curtains 16 a and 16 b from thevertical. Thus, it is desirable to reduce the width of the correspondingintake grille towards the inside of buffer zone 12, When the jetsforming the air curtain Lend to be deviated towards the outside of thiszone. Conversely, the width of the intake grille must be increasedtowards the inside of the buffer zone 12 when the jets forming the aircurtain tend to be deviated towards the inside of this zone.

FIG. 2 illustrates a second embodiment of the invention which isessentially different from the embodiment in FIG. 1 due to the fact thateach air curtain denoted by references 16′a and 16′b comprises threejets of adjacent clean air in the same direction.

This is achieved by providing each of the dynamic confinement meansdenoted by references 14′a and 14′b, in addition to the air supplynozzles 24 a, 26 a and 24 b and 26 b respectively, with a third supplynozzle 34 a and 34 b adjacent to nozzles 26 a and 26 b respectively onthe side of the blower ceiling 18. More precisely, nozzles 34 a and 34 bextend over the entire width of the buffer zone 12 and their output isarranged in the same horizontal plane as the other nozzles 24 a, 26 a;24 b, 26 b, in other words in a horizontal plane which is coincidentwith the plane of the lower surface of the blower ceiling 18.

When dynamic confinement means 14′a and 14′b are implemented, each ofthe air supply nozzles 34 a and 34 b outputs a third clean air jet whichis relatively slow with respect to fast jets emitted by nozzles 26 a and26 b, between this fast jet and the buffer zone 12. The tongues of thesethird jets are illustrated as 36 a and 36 b in FIG. 2.

The dimensions of nozzles 34 a and 34 b are chosen such that the tongues36 a and 36 b of the third jets in each of the air curtains 16′a and16′b cover the entire section of the buffer zone 12. Consequently, thelower slit in each of the nozzles 34 a and 34 b has a width equal to atleast ⅙^(th), and preferably ⅕^(th) of the height of the buffer zone 12,in the cross section parallel to the plane of FIG. 2. In practice, thewidths of nozzles 24 a, 34 a and 24 b, and 34 b are identical.

In the second embodiment of the invention illustrated in FIG. 2, theinjection flow from the slow jets output by nozzles 34 a and 34 b isadjusted to be approximately equal to the injection flow from the slowjets output by nozzles 24 a and 24 b. Thus, the air flows induced by thesurfaces of the fast jets output through nozzles 26 a and 26 b incontact with each of slow jets in the corresponding air curtain, areless than or preferably approximately equal to half of the injectionflows in these slow jets.

As is also shown in FIG. 2, the width of each of the intake grilles 28′aand 28′b is adapted to the width of the air curtains 16′a and 16′b, sothat it is approximately equal to the total width of the nozzles formingthese air curtains. Obviously, this width may be varied as describedpreviously with reference Lo FIG. 1, when the aeraulic conditions in atleast one of the zones 10 a and 10 b tend to deviate the air curtainsfrom the vertical.

The second embodiment that has just been described briefly withreference to FIG. 2 provides dynamic confinement in both directionsbetween buffer zone 12 and each of zones 10 a and 10 b. Furthermore, theclean ventilation air flow injected through the blower ceiling 18 may beconsiderably reduced. The air injection flow through the blower ceiling18 is then equal to at least the air, flows induced by the slow jetsemitted through the injection nozzles 24 a and 24 b, on the surfaces ofthese jets in contact with the buffer zone 12, and it is such that itprovides a minimum speed of 0.1 m/s across the areas of the planes atthe ends of the buffer zone.

In the embodiments described above with reference to FIGS. 1 and 2, thebuffer zone 12 is a passive zone in which no operations are carried outon objects or products that are transferred between zones 10 a and 10 b.

In other embodiments of the invention, the buffer zone 12 is an activezone, in other words it is used to carry out an elementary operation(proportioning, packaging, etc.) on objects or products transferredbetween zones 10 a and 10 b.

The architecture of the dynamic separation device is then identical tothe architecture described above with reference to FIGS. 1 and 2.However, an intake grille is distributed over the entire lower surface20 of buffer zone 12. The intake speed through this intake grille variesfor example between about 0.1 m/s and 0.2 m/s. The internal ventilationsupply flows through the blower ceiling 18 is then larger, and is equalto at least the sum of the air flows induced by each of the surfaces ofthe air curtains in contact with the buffer zone 12 and the intake flowthrough the intake grille.

Furthermore, this internal ventilation supply rate should correspond toa minimum speed of 0.1 m/s across the areas of the planes at the ends ofthe buffer zone.

Note that the ventilation flows through the blower ceiling 18 and theintake flows through the intake grille may be higher. However, theoperating cost of the installation will then be higher.

As shown diagrammatically in FIG. 3, several successive individualoperations (proportioning, packaging, etc.) may be carried out betweenzones 10 a and 10 b during the transfer of objects or products. In thiscase, the dynamic separation device according to the invention willcomprise several buffer zones 12 laid out in series, through which zones10 a and 10 b can communicate. Each buffer zone 12 then hascharacteristics similar to the characteristics described above, andparticularly a blower ceiling 18 and an intake grille 20′ facing it.

In this case, dynamic confinement means denoted by references 14 a, 14 band 14 c are inserted between each pair of adjacent communicating zones.More precisely, dynamic confinement means 14 a are inserted between zone10 a and buffer zone 12 which leads into zone 10 a, the dynamicconfinement means 14 c are inserted between each pair of adjacent bufferzones 12 and dynamic confinement means 14 b are inserted between zone 10b and buffer zone 12 that leads into this buffer zone.

Dynamic confinement means 14 a, 14 b and 14 c are identical with eachother and they may be made as described above with reference to FIG. 1,or as described above with reference to FIG. 2, depending on the case.

As described above, the air curtains formed by the dynamic confinementmeans 14 a and 14 b separating zones 10 a and 10 b are delimited at thesides by side walls 22 of the buffer zones considered which extend intozones 10 a and 10 b, so as to have a width equal to at least the maximumthickness of the air curtains considered.

On the other hand, the air curtains formed by dynamic confinement means14 c that separate two consecutive buffer zones 12 are delimited at thesides by extensions of the side walls 22 of these buffer zones over awidth equal to the width of the supply nozzles forming these aircurtains.

As illustrated as an example in the case of the central buffer zone 12in FIG. 3, note that a single buffer zone can provide dynamic separationof more than two zones 10 a, 10 b and 10 c. In this case, one or severalopenings are formed in at least one of the side walls 22 of the bufferzone considered and each of the openings is controlled by dynamicconfinement means 14 d, the characteristics of which are similar to thecharacteristics of the dynamic confinement means 14 a and 14 b in FIG.1, or dynamic confinement means 14′a and 14′b in FIG. 2.

What is claimed is:
 1. Dynamic separation device comprising: at leastone buffer zone with controlled atmospher configured to connect a firstzone and a second zone; first dynamic confinement means provided betweenthe at least one buffer zone and the first zone to be configured tocreate a first air curtain between the at least one buffer zone and thefirst zone; second dynamic confinement means provided between the atleast one buffer zone and the second zone to be configured to create asecond air curtain between the at least on buffer zone and the secondzone; and each of the first and second air curtains comprising a firstrelatively slow clean air jet and a second relatively fast clean airjet, the first relatively slow clean air jet including a tongue whichsubstantially separates the at least one buffer zone from the first orsecond zones, the second relatively fast clean air jet being configuredto flow on a side of the at least on buffer zone and next to the firstrelatively slow clean air jet in a same direction as the firstrelatively slow clean air jet.
 2. Device according to claim 1, in whichthe said first and second dynamic confinement means are such that thesecond jet in injected at a flow such that the air flow induced by thesurface of the second jet in contact with the first jet is not more thanapproximately half of the first jet injection flow.
 3. Device accordingto claim 1, in which the said first and second dynamic confinement meansare such that each air curtain comprises a relatively slow third jet inthe same direction as the first and second jets and adjacent to thesecond jet on the same side as the buffer zone, the third jet comprisinga tongue that completely closes off communication between the zones andbeing injected at a flow significantly equal to the injection flow ofthe first jet, so that the air flows induced by the surfaces of thesecond jet in contact with the first and third jets respectively are orpreferably appeoximately equal to half of the injection flows of thefirst and second jets.
 4. Device according to claim 1, in which the saidfirst and second dynamic confinement means comprise at least twoadjacent air supply nozzles and air intake grills which face the airsupply nozzles, the air supply nozzles and the air intake grilles beinglocated in two parallel planes, respectively.
 5. Device according toclaim 4, in which the supply nozzles and the intake grilles are locatedin line with an upper surface and a lower surface of the buffer zone. 6.Device according to claim 1 in which the buffer zone comprisesventilation associated with injection means, outputting clean air intothe buffer zone at a flow equal to at least half the sum of the airflows induced by each of the surfaces of the air curtain jets in contactwith the buffer zone, the injection flows being such that it creates aminimum speed of 0.1 m/s across the areas of the planes at the ends ofthe buffer zone.
 7. Device according to claim 6, in which theventilation comprises a blower ceiling.
 8. Device according to claim 6,in which the buffer zone comprises an intake grille distributed over itsentire lower surface, the flow of the injection means being equal to atleast the sum of the air flew at the intake grille and the air flowinduced by each surface of the air curtain jets in contact with thebuffer zone.
 9. Device according to claim 1, in which several bufferzones consisting of side walls, are place in series between the zones tobe separated, the air cutains inserted between two buffer zones beingdelimited by the continuity of the side walls and the air curtainsinserted between a buffer zone and one of the the zones to be separatedare extended by the side walls with a width equal to at least themaximum thickness of these air curtains.
 10. Device according to claim1, in which a single buffer zone composed of side walls is insertedbetween the zones to be separated, the air curtains being extended by apart of the side walls with a width equal to at least the maximunthickness of these air curtains.